Rats subjected to transient forebrain ischemia by the method of four vessel occlusion (4-VO) develop predictable and quantifiable lesions diffusely but also focally in the CA-1 zone of the hippocampus. The distribution and severity of regional hippocampal ischemic neuronal damage is a function of the duration of ischemia. Recent behavioral studies suggest that rats subjected to ischemia show isolated impairments in particular aspects of performance on radial 8 arm maze tasks. Specifically animals with ischemic cerebral damage have impaired "working" memory relative to "reference" memory. We plan to correlate changes in 8 arm maze performance with the extent of morphologic injury, and with alterations in hippocampal blood flow and glucose metabolism. The results from these experiments may provide clues for understanding the relationship between (1) local pathologic neuron damage and alterations in local or distant glucose metabolism and blood flow; and (2) metabolic alteration and behavioral deficit, specifically the glucose metabolism of the CA-zones of the hippocampus and memory for radial 8 arm maze tasks.